JPH07113150B2 - Thin film forming equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thin film forming apparatus for forming a thin film on a semiconductor wafer.

[Background technology]

Generally, when manufacturing a semiconductor device such as an IC, LSI, or transistor, a step of forming a thin film by a method such as vapor deposition or sputtering is required. For example, an Al film is used as a wiring material between elements formed on the main surface of a semiconductor wafer.
The Al film may be formed by a sputtering method. By the way, when the Al film was formed by sputtering, it was found that the adsorbed gas or moisture adhered to the surface of the semiconductor wafer.
It is difficult to obtain a good quality Al film. Therefore, as a pretreatment, the semiconductor wafer is put in a vacuum furnace and baked,
It is necessary to remove the adsorbed gas and moisture on the surface by this baking. Therefore, as shown in FIG. 1, the apparatus for forming a thin film also has a loading unit 1, a baking unit 2, an etching unit 3, a sputtering unit 4, and an unloading unit 5 formed in series to form a semiconductor wafer W in each of the above units. It was considered that the vacuum baking and the sputtering film formation are performed by sequentially moving and processing. The etching part 3 is for removing an oxide film on the surface of the semiconductor wafer, and a so-called dry etching method is adopted.

However, in order to actually form a high-quality Al film,
Vacuum baking must be performed in the baking unit 2 for a sufficient time, and this processing time is longer than the processing time in the etching unit 3 and the sputtering unit 4. For this reason, in the Al film formation using the apparatus of FIG. 1, only the processing time in the bake section 2 becomes long, and even if an attempt is made to continuously process semiconductor wafers with this apparatus, the bake section 2 will be used.
This becomes a bottleneck, making it difficult to form an efficient Al film. If the baking time is shortened in order to improve the processing efficiency, the removal of the adhering water becomes insufficient in particular, a poor quality film is formed, and the throughput is lowered.

[Object of the Invention]

An object of the present invention is to form a thin film of high quality by thin film formation by single-wafer treatment of semiconductor wafers one by one, without being affected by the length of time required for vacuum baking treatment or thin film formation of the semiconductor wafer. An object of the present invention is to provide a thin film forming apparatus that can be formed efficiently.

The above and other objects and novel characteristics of the present invention are
It will be apparent from the description of the present specification and the accompanying drawings.

[Outline of Invention]

The outline of a typical one of the inventions disclosed in the present application will be briefly described as follows.

That is, the thin film forming apparatus of the present invention includes the first and second main bodies, which are provided independently of each other, and the second main body.
Of the semiconductor wafer from the main body of the semiconductor wafer to the first main body, and the first main body individually heats the semiconductor wafers before thin film formation one by one to remove adsorbed gas and adsorbed water on the surface. Vacuum bake part to remove, etching part to remove unnecessary film on the surface by individually etching each semiconductor wafer before thin film formation, film formation to individually form thin film on the surface of etched semiconductor wafer Section, a first loader section for individually supplying semiconductor wafers from the outside to the vacuum bake section, and a first unloader for individually taking out film-formed semiconductor wafers one by one from the film forming section and carrying them out to the outside. The first loader section, the vacuum bake section, the etch section, the film forming section, and the first unloader section, and a plurality of first gated valves partitioning the opening and closing freely. The main body consists of a preliminary vacuum bake unit that removes adsorbed gas and adsorbed water on the surface by heating the semiconductor wafer with a heater provided in a vacuum chamber that houses the semiconductor wafers one by one, and before and after the preliminary vacuum bake unit. A second loader section and a second unloader section, which are arranged and individually carry in and out semiconductor wafers to and from the preliminary vacuum bake section, a preliminary vacuum bake section, a second loader section, and a second unloader. And a plurality of second gated valves for partitioning each of the parts so as to be openable and closable.

[Embodiment 1] FIG. 2 shows an embodiment of the thin film forming apparatus of the present invention. In the figure, 10 is a thin film forming apparatus, which is a loader unit 12 (first loader unit), a vacuum bake unit 13, an etching unit 14, a film forming unit 15,
The unloader section 16 (first unloader section) is integrally arranged in parallel. That is, these respective parts are the gate valves 17 to 22 provided at both ends of the container-shaped main body 11 (first main body) and between the respective parts.
An exhaust pipe 24, which is divided into each chamber by a (first gate valve) and has a vacuum pump 23 interposed, is connected to maintain the inside in a vacuum state. Then, a semiconductor wafer W as a sample on which a thin film is formed on the surface is moved from the loader unit 12 to the unloader unit 16 by an appropriate jig through the gate valves 17 to 22.

The vacuum bake unit 13 has a heater 25 and heats the wafer W in a vacuum state to remove the gas adsorbed on the wafer surface and the adhering moisture. The etching section 14 has an electrode assembly 26 and is connected to an etching gas supply pipe 27, and dry-etches, for example, plasma-etches an unnecessary film such as an oxide film on the surface of the wafer W. The film forming unit 15 has an electrode structure 28 and a target 29 (Al target in this example), is connected to a reaction gas supply pipe 30, and sputters an Al thin film on the surface of the wafer W.

On the other hand, a pretreatment main body 31 (second main body) in the form of a container is independently provided at the previous process position of the main body 11. The pretreatment main body 31 is composed of a loader section 32 (second loader), a preliminary vacuum bake section 33, and an unloader section 34 (second unloader section), and each section is provided with gate valves 35 to 38 provided on the main body 31.
The wafer W is partitioned by the (second gate valve) and moved from the loader unit 32 to the unloader unit 34. Also,
A part of the exhaust pipe 24 is extendedly connected to each part, and each part 32, 3
Make a vacuum inside 3,34. The preliminary vacuum bake unit 33 is kept at a higher vacuum than the loader unit 32 and the unloader unit 33. A heater 42 is installed inside the preliminary vacuum bake unit 33 so that the wafer W moved inside can be heat-treated.

In the figure, 39, 40, 41 are transfer means, respectively, which can transfer the wafer W in the direction of the arrow shown.

Next, the method of the present invention will be described together with the operation of the apparatus of the present embodiment having the above-mentioned configuration. First, the wafer W is carried into the loader section 32 of the pretreatment main body 31 by the transfer means 39, set in the prevacuum bake section 33 through the gate valve 36 while being shielded from the outside air, and heated by the heater 42 ( Bake). As a result, the gas adsorbed on the surface of the wafer W and the attached water are removed. This bake is a relatively short period of time, with most of the gas and water removed but some remains. After that, the wafer W is unloading part 34
Through the main body 31. Even during this period, some gas and moisture are removed from the wafer W by the residual heat.

Next, the wafer W is transferred by the transfer means 40 to the loader section of the main body 11.
It is moved into the inside 12, where it is cut off from the outside air, and is then carried into the vacuum baking section 13 through the gate valve 18. Forever
In this case as well, the wafer W is heated by the heater 25, and gas and moisture are removed in the same manner as described above. In this case, since most of the gas and water are removed from the wafer in the previous step, it is only necessary to remove the residual gas and water, and similarly, almost all the gas and water are removed by baking for a short time.
Water can be removed. Actually, the processing of each of the baking units 33 and 13 can be performed in about half the baking time in the case of performing vacuum baking only once.

The baked wafer W is moved to the etching section 14 through the gate valve 19, where an oxide film or the like on the surface is removed by etching, for example, to expose the surface (active surface) of the wafer. Then, the wafer W is moved to the film forming portion 15 through the gate valve 20 to form an Al thin film by the sputtering method. The thin film formed is 2
Since the adsorbed gas and moisture are well removed by baking in the process, it is of high quality. The film-formed wafer W is moved from the gate valve 21 to the unloader section 16,
Further, after being ejected from the unloader unit 16 to the outside of the main body 11, it is conveyed to the next step by the conveying means 41.

Then, in the series of wafer film forming steps described above,
Since each bake processing time of the preliminary vacuum bake unit 33 and the vacuum bake unit 13 can be reduced to about half that in the case of performing a vacuum bake only once, each bake processing time is reduced to the etching unit 14 or the film forming unit 15.
Can be close to each processing time. Therefore, the processing time in each part of the wafer can be made substantially uniform, whereby continuous processing of sequentially processing the wafer becomes possible, and processing efficiency, that is, film forming efficiency can be increased. Note that, in the present embodiment, the wafer is exposed to the outside air in the transfer means 40, but once vacuum-baked, the amount of water or gas adhering to the wafer again is very small, and there is no problem.

[Effect]

(1) Since the preliminary vacuum bake and the vacuum bake are independently performed by the preliminary vacuum bake section of the second main body and the vacuum bake section of the first main body, which are independent of each other, before the film formation of the wafer.
The time required for each bake can be shortened and a sufficient bake time can be secured to reliably remove adsorbed gas and adhering water, and at the same time, the film forming part, the vacuum bake part and the first unloader part in the first main body. Since the film formation is performed with the first gate valve completely isolated from each other, there is no concern of contamination by external foreign matter in the film formation portion, and a good quality thin film can be formed on the wafer.

Further, even if there is a difference between the time required for the thin film forming process in the film forming unit provided in the first main body and the time required for the preliminary vacuum bake in the preliminary vacuum bake unit in the second main body,
There is no need to wait for each other's processing.

As a result, in thin film formation by single-wafer processing that processes semiconductor wafers one by one, high-quality thin films can be formed with high efficiency without being affected by the length of time required for vacuum baking processing and thin film formation of individual semiconductor wafers. The effect of being able to do is obtained.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments and can be variously modified without departing from the scope of the invention. Nor. For example, vapor deposition or a CVD method may be used for the film forming portion.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an example of a possible device, and FIG. 2 is an overall configuration diagram of an embodiment of the present invention, 12 ... load section, 13 ... vacuum bake section, 14 ... etch section, 15 ... … Film formation part, 16 …… Unload part, 17〜22 ……
Gate valve, 23 ... vacuum pump, 24 ... exhaust pipe, 25 ...
… Heater, 26 …… Electrode structure, 28 …… Electrode structure, 32 …… Load section, 33 …… Preliminary vacuum bake section, 34 …… Unload section, 35 to 38 …… Gate valve, 39 to 41 …… Transfer Means, 42
……heater,

Claims (1)

[Claims] 1. A first main body and a second main body, which are provided independently of each other, and a transfer means for transferring a semiconductor wafer from the second main body to the first main body. Is a vacuum bake unit that individually heats the semiconductor wafers before thin film formation to remove adsorbed gas and adsorbed moisture on the surface.Each semiconductor wafer before thin film formation is individually etched to eliminate the need for surface. An etching part for removing a film, a film forming part for individually forming a thin film on the surface of the semiconductor wafer after etching, and a semiconductor wafer for external supply to the vacuum bake part one by one A loader section, a first unloader section for individually taking out the film-formed semiconductor wafers one by one from the film forming section and carrying them out to the outside, the first loader section, the vacuum bake section, the A plurality of first gated valves for partitioning each of the switch portion, the film forming portion and the first unloader portion so as to be openable and closable, and the second main body accommodates the semiconductor wafers one by one. By heating the semiconductor wafer with a heater provided in a vacuum chamber, a preliminary vacuum bake unit for removing adsorbed gas and adsorbed moisture on the surface, arranged before and after the preliminary vacuum bake unit, for the preliminary vacuum bake unit. Between each of the second loader unit and the second unloader unit that individually carry in and carry out the semiconductor wafers one by one, the preliminary vacuum bake unit, the second loader unit, and the second unloader unit. A thin film forming apparatus comprising: a plurality of second gate valves for partitioning the opening and closing.